“Even after controlling for publication volume and field”

Suppose you find:

Elite-university historians receive more citations.

You might initially think:

“Perhaps they receive more citations simply because they publish more.”

So you compare scholars who publish approximately the same number of articles.

Suppose:

Elite institution: 20 articles then 2,000 citations

Less prestigious institution: 20 articles then 800 citations

Now publication volume is less likely to explain the difference.

But there is another problem:

Maybe elite-university historians work in more popular fields.

Suppose:

Scholar A studies a heavily researched subject.

Scholar B studies an obscure subject.

A naturally has more opportunities for citations.

So researchers can also control for field.

In simple terms:

Control for publication volume = compare scholars with similar amounts of published work.

Control for field then compare scholars working in similar academic areas.

The purpose is to ask:

Does institutional prestige still appear associated with citation after these other explanations have been taken into account?